Category: Composite

ASTM D7905

Standard Test Method for Determination of the Mode II Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Polymer Matrix Composites

ASTM D7136

Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer Matrix Composite to a Drop-Weight Impact Event

ASTM D7028

Standard Test Method for Glass Transition Temperature (DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA)

ASTM D5766

Standard Test Method for Open-Hold Tensile Strength of Polymer Matrix Composite Laminates

ASTM D5528

Standard Test Method for Mode I Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Polymer Matrix Composites


 Interlaminar Fracture Toughness by Double Cantilever Beam Method

This method determines the interlaminar fracture toughness of a material by applying a constant tensile force to a bond to induce a crack.  The surfaces are pulled apart without sliding or shearing.

After appropriately conditioning and machining the specimens, a specimen is placed into the fixture and the machine begins to separate the specimen by pulling apart at the crack opening to a pre-specified distance.  The machine then returns to the zero extension point so that a calculation can be performed for the area within the curve produced.

Interlaminar toughness.

Equipment Used:
Test frame, double cantilever beam test fixture.

ASTM D7264

Standard Test Method for Flexural Properties of Polymer Matrix Composite Materials

This test is designed for testing of flexural properties of polymer matrix composites by using a coupon of a rectangular cross section supported by two parallel beams set to a specific support span and deflected at a constant rate from the center of the span.

This test contains two procedures.  Procedure A involves a three point loading system, while procedure B utilizes a four point loading system.  Each procedure requires different calculations for strain due to the different deflections per each system.

Flexural strength, maximum flexural stress, maximum strain, modulus of elasticity, failure mode, location of failure.

Equipment Used:
Test frame, four point flexural fixture, three point flexural fixture.

ASTM D6484

Standard Test Method for Open-Hole Compressive Strength of Polymer Matrix Composite Laminates

This method is used for determining the compressive strength of polymer matrix composite laminates that are reinforced by high-modulus fibers.  The standard also limits the material types to those which employ continuous fiber, or discontinuous fiber reinforcement. The laminate must also be balanced and symmetric with the test direction.

After the appropriate conditioning and machining, the specimen is inserted in the fixture with the proper torque specifications met at the bolt interfaces. The fixture is placed between flat platens in the testing machine.  Extensometers can be adhered to determine strain.  The machine is put under load and the test proceeds until the force has dropped of approximately 30% from the maximum.

Ultimate open-hole compressive strength, maximum force prior to failure, open-hole compressive strain.

Equipment Used:
Extensometer, Test frame, open hole compressive strength fixture.

ASTM D5379

Standard Test Method for Shear Properties of Composite Materials by the V-Notched Beam Method (Iosepescu)

This test is used to determine the shear properties of composite materials reinforced with high-modulus fibers.  This method is also particular to discontinuous and continuous fiber composites with only material forms that are specified in the standard.

After conditioning and machining the specimen according to the standard, strain gauges must be applied in a very specific fashion to ensure proper readings.  The two strain gauges also ensure that there is no specimen twisting through analysis of the test data.  The load is applied by the universal testing machine until failure occurs.

Shear stress, ultimate strength, shears strain, ultimate strain, and shear cord modulus of elasticity.

Test frame, IOSEPESCU Shear Test Fixture, two strain gauges, test method software.